Showing 1 - 10 of 34 Journals Results
2020
UKAEA-CCFE-PR(20)135
M.S. Anastopoulos Tzanis C.J. Ham P.B. Snyder H.R. Wilson
The poloidal harmonics of the toroidal normal modes of an unstable axisymmetric tokamak plasma are employed as basis functions for the minimisation of the 3D energy functional. This approach presents a natural extension of the perturbative method considered in [M.S. Anastopoulos Tzanis et al, Nuclear Fusion 59:126028, 2019]. This variational formul…
Preprint Purchase2020
UKAEA-CCFE-PR(20)77
D. Brunetti C. J. Ham J. P. Graves C. Wahlberg W. A. Cooper
Anisotropy and some limiting toroidal flow effects on the stability of non resonant ideal magnetohydrodynamic modes in hybrid shaped tokamak plasmas are investigated within the ideal MHD infernal mode framework. Such effects are found to alter the plasma magnetic well/hill, which can be interpreted as imparing the average curvature, and the stre…
Preprint Published2019
UKAEA-CCFE-PR(20)121
Guoliang Xia Yueqiang Liu L. Li C. J. Ham Z . Wang Shuo Wang
Effects of parallel and poloidal flows, as well as the flow shear, on the resistive wall mode (RWM) instability have been numerically investigated in toroidally rotating plasmas, utilizing a recently updated version of the MARS-F code (Liu Y Q et al 2000 Phys. Plasmas 7 3681). A significant difference between these flow…
Preprint Published2018
UKAEA-CCFE-PR(20)22
M.S. Anastopoulos-Tzanis B.D. Dudson C.J. Ham C.C. Hegna P.B. Snyder H.R. Wilson
A linear perturbation theory is used to model the MHD stability of tokamak equilibria under the application of external 3D magnetic perturbations [C.C. Hegna, Physics of Plasmas 21 :072502, 2014]. The symmetry breaking produces the coupling of toroidal n modes. We use ELITE [H.R. Wilson et al., Physics of Plasmas 9 :1277, 2002] to produ…
Preprint Published2019
UKAEA-CCFE-PR(19)39
Christopher Ham Andrew Kirk Stanislas Pamela Howard Wilson
Fusion is one of very few options for sustainable, baseload power to the grid that is necessary to meet the energy needs of future generations. The tokamak is the most advanced approach to fusion and, with the construction of ITER, we are approaching power plant conditions. While commercialisation of this key technology is a main driver for tokamak…
Preprint Published2019
UKAEA-CCFE-PR(19)18
D A Ryan M Dunne A Kirk S Saarelma W Suttrop C Ham Y Q Liu M Willensdorfer the ASDEX Upgrade team the MST1 team
A numerical survey of the plasma response in ASDEX Upgrade ELM control experiments is conducted, to clarify the role of triangularity in the suppression mechanism. The pedestal pressure increases with triangularity consistent with previous work [2], which modestly boosts the peeling response. However, the peeling response decreases with increasi…
Preprint Published2018
UKAEA-CCFE-PR(19)09
J W Connor C J Ham R J Hastie A Zocco
Kinetic treatments of drift tearing modes that match an inner, resonant layer solution to an external MHD solution, can fail to match the ideal MHD boundary condition on the parallel electric field. In this paper we demonstrate how consideration of ion sound and ion Landau damping effects achieves this, placing the theory on a firm footing. The …
Preprint Published2018
UKAEA-CCFE-PR(18)69
M. Willensdorfer T.B. Cote M. Griener D.A. Ryan E. Strumberger W. Suttrop N. Wang M. Cavedon S.S. Denk M. Dunne R. Fischer J. Galdon-Quiroga C.J. Ham C.C. Hegna M. Hoelzl A. Kirk M. Maraschek F. Mink N. Leuthold F. Orain E. P. Seliunin H. Zohm the ASDEX Upgrade Team and the MST1 Team
The impact of the three-dimensional (3D) tokamak geometry from external magnetic perturbations (MPs) on the local edge stability has been examined in high confinement mode (H-mode) plasmas with edge localised modes (ELMs) in ASDEX Upgrade. The 3D geometry has been probed using rigidly rotating MP fields. The measured distortions of the plasma bound…
Preprint Published2018
UKAEA-CCFE-PR(18)61
Guoliang Xia Yueqiang Liu C. J. Ham Shuo Wang Li Li G. Y. Zheng J. X. Li N. Zhang X. Bai G. Q. Dong the HL-2M team
Effects of toroidal plasma flow, magnetic drift kinetic damping as well as feedback control, on the resistive wall mode instability in HL-2M tokamak are numerically investigated, using the linear stability codes MARS-F/K (Liu Y Q et al 2000 Phys. Plasmas 7 3681, Liu Y Q et al 2008 Phys. Plasmas 15…
Preprint Published2017
CCFE-PR(17)66